Marvel's much-anticipated Captain America: The Winter Soldier opens in just about two weeks, but there has already been some news about that film's eventual follow-up.  Recently, it was revealed that Captain America 3 would be opening on May 6, 2016 (the same day as WB's Man of Steel sequel).  We know that Joe and Anthony Russo will return for the third film, and that they're currently breaking the story with returning screenwriters Christopher Markus and Stephen McFeely.  While promoting the upcoming film, the screenwriters may have let slip the comics source for the framework of the plot of the next installment.  Hit the jump to get a little crazy.

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In an interview with Den of Geek (via BC), Markus and McFeely grudgingly shared this little plot nugget for Captain America 3:

Are you going back to the comics for the next one and plan to adapt another story, while incorporating the many threads left open at the end of this one?

McFeely: Oh yeah, you can probably predict some of the threads we would like to pick up again that we’ve laid out there. And we always go back to the comics and dive back in and look at anything we’ve missed in the last few years that might be relevant.

Markus: We’ve definitely set out on a more realistic road in the Cap movies, you know. Even more grounded than in the other MCU movies. And so it kind of rules out Cap fighting the Dinosaur Man or something like that. There are some that aren’t gonna start and other ones that -- I mean there’s a couple we’re playing with right now that we really want to take elements from. Which we'll not reveal.

Oh, come on.

Markus: All I’m saying is psychotic 1950s Cap.

That last comment likely excited longtime Cap comics fans, but probably doesn't mean much to newcomers to the property.  While the Winter Soldier storyline is a pretty ambitious journey to undertake, the storyline Markus could be referencing is even crazier.  Here's an attempt to give you the short version:

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Continuously published from 1941 to 1949, Captain America was relaunched in the 50s to little fanfare.  The stories featured both Cap and Bucky taking on an obviously Communist Red Skull.  This plotline was more or less forgotten - even by Stan Lee himself - and Cap was revived again in 1964, along with the story that he'd been in a state of suspended animation since the end of World War II.  This revelation placed the 50s run out of canon, until a 1972 Steve Englehart run that attempted to explain the anomaly in a bit of retroactive continuity.

This explanation posited that "an unnamed man and his teenaged student had assumed both the public and private identities of the original Captain America and Bucky as part of a government-sponsored program which planned to replace the lost heroes to combat the "red threat" (i.e. communism)." (Via Wikipedia) The Super-Soldier Serum for this pair, however, was flawed, and led them to develop psychotic side-effects.  The government then placed these failed subjects in suspended animation, until they were revived years later to battle the current iteration of heroes.

Pretty crazy stuff, but that's just the tip of the iceberg.  "1950s Captain America", or Captain America IV as he was also known, also once assumed the identity of the "Grand Director", a leader of a Neo-Nazi force.  His name was recently revealed to be William Burnside, so if you see it pop up, it's this whole insane storyline that's being referenced.  Good luck researching this one down the rabbit hole!

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